Deadwood basic density values for national-level carbon stock estimates in Italy

Abstract

Deadwood biomass is one of the five terrestrial carbon pools that are relevant for the estimation of carbon stocks and carbon stock changes under the UNFCCC and the Kyoto Protocol (IPCC Guidelines for National Greenhouse Gas Inventories). Statistics on this important ecosystem component are generally provided by national forest inventories: in the last few decades, national forest inventories in Europe have gradually included deadwood among the traditionally investigated components. However, deadwood is generally surveyed in terms of volume, which is then converted to biomass using basic density values. These are rarely specifically derived for the population under estimation; more often, values available from the literature and based on the findings of local studies are used instead. Based on a survey conducted by the Italian national forest inventory in 2008 and 2009 that specifically intended to more deeply investigate the carbon storage of forests, samples of deadwood were collected all over the country from the plots of the national forest inventory network and used to derive basic density values. This paper presents the basic densities obtained for groups of species (conifers, broadleaves), deadwood components (coarse woody debris, standing dead trees, stumps) and decay classes (using a five-class system). Fine woody debris was also surveyed, but in terms of weight and not volume. For such material, the ratio of dry weight to fresh weight for conversion to biomass is presented. In addition, the main aspects of the field protocol are discussed. Lastly, the use of less accurate, generalised basic density values is tested to evaluate its effects on deadwood biomass estimates.